Semiconductor devices frequently utilize discrete inductors which are typically placed external to the integrated circuit die or chip and external to the package containing the integrated circuit die. As a result, long interconnects are usually provided to connect the inductor to the die. These interconnects can frequently have high impedances and can result in large ohmic losses. Also, in high-density circuit board fabrication, it is often difficult to provide sufficient space outside the die package for the discrete inductors.
Integrated inductors may be formed by depositing one or more metal layers in or on a package substrate or a die substrate. Thus, a spiral wound inductor can be deposited in a single conductive metal layer on a substrate. However, spiral inductors tend to be relatively large, occupying valuable substrate space, in order to provide sufficient inductance for the particular application. Multiturn inductors may also be formed in a helix configuration in which windings are deposited in multiple layers embedded in the substrate. However, such multilayer structures can be difficult and expensive to manufacture. Furthermore, integrated inductors tend to have high resistances which can adversely affect the quality factor. As a result, the quality factor of the inductor may be relatively low such that the inductors may be too lossy for some applications such as power delivery.